Dear Colleagues,

REBOCC MT inversion is now available for download.

Information about REBOCC
------------------------
 o  What is REBOCC ?

   REBOCC is an inversion program for 2-D Magnetotelluric (MT) data.
   REBOCC stands for REduced Basis OCCam's Inversion.
   It is based on an efficient variant on the OCCAM algorithm of
   deGroot-Hedlin and Constable (1990).

   Currently, REBOCC can invert apparent resistivity and phase of TM
   and TE modes, as well as the real and imaginary parts of the
   vertical magnetic transfer function (TP) -the ratio between the
   vertical magnetic field and the horizontal magnetic field.

 o  Why uses REBOCC ?

   x  Fast
     Numerical experiments (Siripunvaraporn and Egbert, 1999) show that
     the speed of REBOCC is competitive with RRI (Smith and Booker, 1991),
     generally faster than NLCG (Rodi and Mackie, 1999), and
     significantly faster than OCCAM (deGroot-Hedlin and Constable, 1990).

   x  Stable
     REBOCC converges more reliably than some approximate inversions.

   x  Moderate memory requirement
     Large data sets can be inverted with REBOCC.  It has been tested on
     a Sun UltraSparc I (with 288 Megabytes of RAM) on a very large
     problem: joint inversion of 55 stations, 41 periods and 2 responses
     for TM mode, 37 stations, 41 periods and 2 response for TE mode and
     15 stations, 41 periods and 2 response for TP data (or total number
     of data = 8774) and total number of model parameter of 14800
     (74 X 200).

   x  Easy to use
     Default options and keywords (provided for input parameters),
     generally, work well.  We also provide a user manual.
     The program is written entirely in standard FORTRAN 77.
     Compilation with any standard Fortran compiler should be
     straightforward.  To date REBOCC has been tested and run on Sun
     workstations running Solaris and IBMs running AIX.

 o  What is the condition on using REBOCC inversion ?

   REBOCC is freely available for academic use.  It cannot be used for
   any commercial purposes without written permission from the authors.

 o  Update and bug fixed ?

   If you download the program, please send your name and email address to
              wsiripun@oce.orst.edu or egbert@oce.orst.edu
   so that we can put your name into an update and bug report list.

 o  Where to download ?

   The program can be downloaded via anonymous ftp at

   ftp.oce.orst.edu   in   /pub/wsiripun/rebocc

   or point your browser to

   ftp://ftp.oce.orst.edu/pub/wsiripun/rebocc

   and click at the file to download.

   x  rebocc.tar.gz    is for gzipped source.
   x  rebocc.tar.Z     is for compressed source.

   Note that in the case that you can not find the directory,
   please contact the authors directly for the new location.

 o  How to install the program ?

   After downloading the program, at the command line

   gunzip rebocc.tar.gz

   or
   uncompress rebocc.tar.Z

   to get rebocc.tar file.
   Then type

   tar xf rebocc.tar

   at the command line. You should get four directories.

   x  /data/ contains examples of the data input files.
   x  /docs/ contains documents, including this documentation and a
      preprint of Siripunvaraporn and Egbert (1999).
   x  /examples/ contains examples of the startup files.
   x  /src/ contains Fortran source codes.


 Weerachai Siripunvaraporn and Gary Egbert
 (wsiripun@oce.orst.edu)       (egbert@oce.orst.edu)
 Oregon State University
 January 29, 1999.